SEWER SYSTEMS

Pressure Sewer Systems vs Gravity Sewer Systems

Benefits of Pressure Sewer Systems

As communities migrate from septic tanks to central sewer systems, they will consider pressure sewer and gravity sewer systems. "The Secret Life of Pressure Sewers" details the benefits of pressure sewer systems - for one, they use small, 2- to 4-inch force mains that follow the contour of the land and are installed just below the frost line, eliminating the need for large, deep trenches.

Pressure Sewer vs Gravity Sewer

Soil conditions can also make pressure sewer a better choice than gravity sewer. Elwood, Missouri, has soft, loamy soil conditions and relatively flat land. The gravity sewer system was prone to infiltration - lift stations ran constantly to pump out groundwater, and collapsed mains and roadways were common. When the town was washed out by the Flood of 1993, Elwood rebuilt the sewer system using pressure sewer and E/One grinder pumps. Infiltration problems were eliminated, saving thousands of dollars in maintenance costs.

Gravity sewer systems may also require large, expensive lift stations. Great Sky in Canton, Georgia, is a new residential development. A gravity sewer system would have required 20 lift stations because of the steep, hilly terrain. A pressure sewer system cut the number of required lift stations to three.

Sewer System Upgrades: Eliminating Infiltration & Inflow

New video! View our new video, E/One Infiltration & Inflow Solutions. As communities face aging sewer infrastructure, many are turning to E/One pressure sewer systems for the solution. This video describes how communities can save tens of thousands of dollars on treatment and repair costs.

The use of SPD grinder pumps is crucial to the success of a pressure sewer system. The performance characteristics of SPD pumps assist in maintaining a sewer network free from blockages. When deposition of solids occurs, tending to block the pipe, centrifugal pumps will move toward shut off, reducing flow and velocity and increasing the tendency to block the pipe. SPD pumps constantly scour the lines to prevent buildup because flow is maintained although pressure or head increased, effectively scouring the pipe.

Q:How is growth in the community handled?A: Typically, pressure sewer systems are designed for future growth. When designed properly, additional zones can be added as the community grows. New developments will require analysis as they would if a gravity system was used. Existing communities can manage growth simply by adjusting the diameter of the street mains to meet only current or projected future needs.